Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
FXUS62 KRAH 010153
Area Forecast Discussion
National Weather Service Raleigh NC
955 PM EDT Tue May 31 2016
.SYNOPSIS...The remnant circulation of Tropical Storm Bonnie
will continue to drift slowly northeast just off the Carolina coast
through Thursday. A cold front will approach the region from the
west late in the work week and then stall in our region.
.NEAR TERM /through Wednesday night/...
As of 955 PM Tuesday...
Late afternoon-early evening convection has pretty much diminished
as of 0130z, with isolated showers confined to locations near
Sanford and south of Rockingham. Latest meso-analysis depicts the
best low-mid level convergence in vicinity of our central/southern
coastal plain, in conjunction where deeper moisture resides. Spokes
of vorticity pivoting around the remnants of Bonnie, currently
located offshore of Wilmington, will graze our se quadrant
overnight. Thus, cannot entirely rule out an isolated shower, mainly
east of highway 1 and south of highway 64, through daybreak.
Similar to last night, could see pockets of fog with reduced
visibility as low as a mile or a half mile develop after midnight,
particularly at locations where heavy showers were experienced
earlier (Rockingham, Clinton, Raleigh, Sanford). In addition, expect
areas of low clouds to develop with the greatest probability of low
clouds occurrence over the coastal plain and ne Piedmont.
Expect a continuation of the warm and humid conditions with
overnight temps in the 65-70 degree range expected. -WSS
A persistence forecast will be used for Wednesday and Wednesday
night with the surface and mid level circulation associated with the
remnants of Bonnie expected to move little and with very little air
mass change across NC. CAMs again highlight an area of scattered
convection across the Coastal Plain that pushes west with coverage
that is not surprisingly a little bit more limited than the previous
day. Convection will be diurnally driven and should tape off after
sunset. While the air mass is again weakly unstable, limited
updraft strength and shear should preclude and severe weather
concerns. Highs should be similar to perhaps a degree warmer than
today and range in the lower to mainly mid 80s with lows Wednesday
night in the mid to upper 60s. -blaes
.SHORT TERM /Thursday through Friday night/...
As of 255 PM Tuesday...
Remnants of post-tropical storm Bonnie will linger under short wave
ridging aloft and remain nearly stationary along the central NC
coast on Thursday. The ridging is tamped down Thursday night and
Friday due to eastward progression of a strong short wave across the
Great Lakes. This will modestly increase westerly flow and nudge the
remnant low offshore Thursday night and Friday. We will see a lull
in the threat of convection over most of the area on Thursday as the
remnant low wraps more stable in from the north. Moisture will begin
to edge into the west by late day, however, in increasingly westerly
flow which will be fed moisture off the western gulf by a closed
low over Texas.
Will maintain ongoing small chances for convection in the east
Thursday as precipitable water will remain above 1.5 inches with mid
level lapse rates exceeding 6K/km to enhance instability. Highs will
benefit from periods of sun to reach the mid 80s, with perhaps some
upper 80s in the southeast. Precip chances will diurnally fall off
Thursday night concurrent with the low moving offshore, and mins
will be seasonable, in the upper 60s. More unsettled weather with
increasing convective coverage will return quickly on Friday as a
cold front very slowly sags south out of the Ohio Valley to provide
a convergence zone to enhance lift in the moisture rich environment.
Highs are potentially in the upper 80s across the area, but heavier
cloud coverage in westerly flow would temper that down a bit to mid
80s north and upper 80s across the southern tier. The frontal zone
will be in the vicinity Friday night, perhaps even lying across the
area per latest GFS, keeping chance of ongoing showers overnight
with persistence mins near 70.
.LONG TERM /Saturday through Tuesday/...
As of 255 PM Tuesday...
Upcoming weekend still looks wet but confidence is not high as there
are a number of details that will determine the coverage and
intensity of convection. The cold front sagging south aligns
parallel to the upper flow and stalls in the vicinity of the area
and makes a jog back to the north as a stronger short wave rotates
across the Ohio Valley. Will have a strong warm and moist advection
on Sunday as this wave pushes a much stronger cold front across the
area Sunday night. As such, will modestly nudge the PoPs up both
Saturday but particularly Sunday due to the relative consensus of
model solutions. Highs will be persistence in the unchanged airmass,
with mid to upper 80s, with the potential for some very low 90s
in the south given an extra hour or two of sunshine.
Dryness returns Monday and Tuesday as the upper system pushes
offshore with somewhat cooler and dry ridging building in through
mid week. Highs Monday and Tuesday will be pleasant, in the low
80s after morning lows in the mid 60s.
.AVIATION /00Z Wednesday through Saturday/...
As of 840 PM Tuesday...
VFR conditions are expected to continue this evening outside a few
lingering isolated showers/storms. Stratus and fog will likely
develop again late tonight although later than previous nights and
with reduced coverage and duration than previous nights, with the
best chance at KRWI/KFAY (MVFR-IFR). The stratus and fog should
quickly dissipate/lift by around 15Z Wednesday morning.
Additional bands of isolated to scattered showers and storms will be
possible Wednesday morning into the afternoon again, with the best
chance across eastern portions of the area as the remnant
circulation of Bonnie slowly moves north-northeastward near the
coast of NC. Sub-VFR conditions and gusty winds will be possible
with the strongest storms (generally in the afternoon).
A repeat of MVFR/IFR stratus/fog is expected to develop Wednesday
night. Chances of afternoon/evening storms on Thursday decrease a
bit compared to previous days before increasing again on Friday into
Saturday as a cold front approaches from the west.